Objective: It is unknown if in axial spondyloarthritis (axSpA) patients' illness perceptions and coping strategies change when disease activity changes.
Methods: Patients diagnosed with axSpA and with 1 or more follow-up visits (1 and/or 2 yrs in the SPACE cohort) were included. Mixed linear models were used for illness perceptions (range 1-5), coping (range 1-4), back pain (numeric rating scale range 0-10), health-related quality of life (range 0-100), physical and mental component summary (PCS and MCS; range 0-100), work productivity loss (WPL; range 0-100), and activity impairment (AI; range 0-100%), separately, to test if they changed over time.
Results: At baseline, 150 axSpA patients (mean age 30.4 yrs, 51% female, 65% HLA-B27+) had a mean (SD) numeric rating scale back pain of 4.0 (2.5), PCS of 28.8 (14.0), MCS of 47.8 (12.4), WPL of 34.1% (29.8), and AI of 38.7% (27.9). Over 2 years, clinically and statistically significant improvements were seen in the proportion of patients with an Ankylosing Spondylitis Disease Activity Score (ASDAS) of low disease activity (from 39% at baseline to 68% at 2 years), back pain (-1.5, SD 2.2), AI (-14.4%, SD 27.2), PCS (11.1, SD 13.3), and WPL (-15.3%, SD 28.7), but MCS did not change (0.7, SD 13.9; P = 0.201). In contrast, illness perceptions and coping strategies did not change over a period of 2 years. For example, at 2 years patients believed that their illness had severe "consequences" (2.8, SD 0.9) and they had negative emotions (e.g., feeling upset or fear) towards their illness ["emotional representation", 2.5 (0.8)]. Patients most often coped with their pain by putting pain into perspective ["comforting cognitions", 2.8 (0.6)] and tended to cope with limitations by being optimistic ["optimism", 2.9 (0.7)].
Conclusion: While back pain, disease activity, and health outcomes clearly improved over 2 years, illness perceptions and coping strategies remained remarkably stable.
Keywords: back pain; illness behavior; quality of life; spondyloarthritis; work performance.